lim(x→+∞)5x^2+2x+1/2x(x+1)

几道求极限的高数题,lim1/x(tanπx/(2x+1)) x→∞lim x(x^x-1)x→0+lim(x^x^x- lim(x→∞)[sinx/x+xsin(1/2x)] lim(x→∞)[(a x^2)/x+1]+bx=lim(x→∞)(a x^2)+bx(x+1) / x+1=lim(x 求lim(x→0)x cos 1/x lim(x→∞)x^2/ (3x-1)的极限 lim(x→∞)[(X^2+2x+5)/(4x^2-x+1) =(1+2/x+5/x^2)/(4-1/x+1/x^2)= 1.4求极限lim(x→∞) (x^2+x)/ (x^4-3x^+1) lim(x→∞)(x^2+x)/(x^4-3x-1)的极限 求极限lim(x→∞)[(2x+5)/(2x+3)]^(x+1) lim(√(4x²-8x+5)+2x+1),x→-∞怎么解? lim(x^2+1/x^2-2x)^x=? lim(x->0)((2-x)/(3-x))^1/x lim(x→0)ln(1-2x)/x